bnx2x: Clear MDC/MDIO warning message

This patch clears a warning message of "MDC/MDIO access timeout" which may
appear when interface is loaded due to missing clock setting before resetting
the LED, and starting periodic function too early.

Signed-off-by: Yaniv Rosner <yanivr@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>